This invention relates to a rotating bowl decanter centrifuge.
In the process of separating heavier phase material from lighter phase material, a solid from a liquid for instance, a rotating bowl decanter centrifuge is often utilized. The centrifuge has a bowl cavity which includes a clarifier section to separate the materials by reason of density differences under the action of centrifugal force. The heavier phase materials are deposited radially on the bowl wall, and move longitudinally along that wall to a beach section. The bowl wall conventionally has a zero incline angle, i.e., the wall is the same distance from the bowl axis throughout the clarifier section.
Conventionally, both the clarifier and beach sections include a conveyance device utilized to transport the heavier phase material from the clarifier section to the beach section, and thence toward the heavier-phase discharge end of the centrifuge. Often these conveyance devices comprise one or more co-axial rotating helical conveyers operating at a speed differential with respect to the rotating bowl. That segment of the conveyor situated in the clarifier section acts to move the sedimented heavier phase toward the beach.
The conveyor serves several purposes in the clarifier section. It acts to move the sedimented heavier phase toward the beach. In so doing, it also raises the level of the heavier phase interface in the centrifugal force field, and thereby reduces the radial distance by which the heavier phase has to be "lifted" by the beach. The conveyer also helps to impart rotational velocity to the feed, thus promoting the centrifugal force field necessary for a high rate of sedimentation.